Outline

Introduction: Since Autumn 2002, a Program of Universal Neonatal Hearing Screening (UNHS) has been introduced to whole Poland. It includes 3 diagnostic levels. The first one takes place in all (c.500) neonatological units in Poland. Over 98% of newborns have been examined (over 1,000,000 ). Infants at about 3 months of age enter the second level of the Program. Over 50 audiological council centres organize this level of the Program. Infants are examined during 1-day hospitalization. The third level aims to fit with hearing aids early (before 6 months) and to begin with rehabilitation. When the profound hearing loss is diagnosed, the qualifications for cochlear implants starts. The UNHS Program has been initiated and partly sponsored by the Foundation of Great Orchestra of Christmas Charity.

Aim: The aim of this study is to show our findings of hearing ability in infants examined in the Department of Phoniatrics and Audiology in Poznan. All the babies were examined by The Universal Newborn Hearing Screening Program during 2002–2007 in second and third level.

Material: 2500 children have been admitted to the Department of Phoniatrics and Audiology. They were referred from neonatological wards with refer results or because of risk factors of hearing loss in the anamnesis. The methods of audiological examinations were: DPOAE, impedance audiometry and ABR.

Results: 3382 of DPOAE tests, 1753 of ABR tests and 1020 impedance tests were performed. Children were divided into 2 groups: 1. with pass result in DPOAE, without risk factors of hearing disorder in anamnesis; 2. with refer result or with risk factors of hearing disorder.

Infants from the second group had the impedance audiometry and ABR tests performed (cross check principle) to state the hearing threshold and define the type of hearing loss.

8.7% (218) children were fitted with a hearing aid; 2.6% (65) children qualified to the Cochlear Implants Program and 2.4% (59) of them underwent the cochlear implant surgery 0.8% (22) of these were before the second year of their lives. The detailed results of the hearing screening examinations are: binaural conductive hypoacusis was diagnosed in 6%, unilateral perceptive hearing loss in 2.8% and bilateral perceptive hearing loss in 3.6%. In three cases we diagnosed neuropathy of 8th nerve. In 87.6% of children examined in 2nd level of Newborn Screening hearing disorders were not confirmed.

Introduction

Late diagnosis of hypoacusis is the main cause of speech disorders, retardation or even complete lack of speech development. Introduction of the program of obligatory auditory screenings in neonates in Poland fulfilled the postulate of the 1998 European Consensus (Milan) concerning early diagnosis of hearing impairment.

In 2002 experts from the Great Orchestra of Christmas Charity Foundation (WOSP) in cooperation with the Polish Neonatal Society decided to organize the IX Orchestra's Great Finale under the subject of checking sight and hearing in neonates. Experts in neonatology, laryngology, audiology, phoniatrics, engineering, and IT specialists were invited to support the project and the Program Board for auditory screenings was appointed. The "PPBSN" program began in autumn of 2002.

The aim of the PPBSN program is examining the condition of the organ of hearing in all neonates in Poland and the earliest possible hypoacusis detection but also appling proper rehabilitation procedures to the age of 6 months. The program consists of three diagnostic levels. The first level is carried out in all obstetric and neonatal wards in Poland (ca 449 institutions). During stay on the neonatal ward every child whose mother granted permission is given a questionnaire of hearing impairment risk factors.

Information gathered in an interview of newborns from the risk group of hearing loss allows for proper planning of individual schedule of tests every child should undergo during the first three years of his life. Children undergo the first test in their second or third day of life. The Program Board has chosen acoustic otoemission (TEOAE) as the testing method – it records sound responses to an acoustic stimulus by external hear cells of the cochlea. It is a non-invasive method, short and easy to conduct and automatically recorded. Normal OAE results and negative interview concerning risk factors finish the test. Newborns are given a certificate confirming they have undergone the screening with normal hearing results.

In case of abnormal results the test is repeated before the newborn is discharged from the ward. If the incorrect result is confirmed the newborn is referred to an institution of second level of reference.

The second level of reference are institutions of audiological and laryngological diagnostics. At least one such centre was created in every province (50 of them operating by now). The tasks of these institutions are rescreening and, in case of confirmed hypoacusis, full audiological testing.

The methodology include:

verification of risk factors of hearing impairments and observation of child's hearing behavior,

laryngological examination with external auditory meatus evaluation,

DPOAE measurement.

Positive result of the testing (pass) finishes the auditory screening. Negative result – no otoemission (refer) is an indication for further audiological diagnostics, determining the type and degree of hearing defect (impedance audiometry, ABR).

Children below the age of six months are referred to the third level of reference centers, which perform the ABR audiological test with hearing threshold reconstruction. Infants diagnosed with hypoacusis less then 40 dB are fitted with hearing aids and begin rehabilitation and specialist auditory and surdologopedic trainings. After 3–6 months of training the pre-audiological assessment is repeated. If the cochlear implant is required children have to underwent CI qualification procedure in the first year of age. Figure 1 [Fig.Â 1] shows the scheme of diagnostic procedures in children who have undergone the PPBSN screening program.

According to the principles of the PPBNS program infants with hypoacusis, who are treated and rehabilitated, should consult the audiological centers at least every six months for hearing control.

Material and methodology

The Department of Phoniatrics and Audiology of the Medical University in Poznan carries out the second and third level of the PPBSN Program. 2500 infants were referred from the neonatal wards to undergo the tests if:

their first stage auditory screening resulted in REFER, i.e. if no otoacoustic emission at least in one ear was diagnosed,

their history indicates risk factors of hearing loss, (although their first level of reference screening resulted in PASS),

they were infants from other second level of reference centers with preliminary suspicion of hypoacusis.

The methods of the audiological screening enclosed DPOAE otoacoustic emission measurement, impedance audiometry and ABR. Tests were carried out in a soundproof room while neonates were awake or in a natural sleep.

Results

Between autumn 2002 and 2008 2500 infants, including 1220 girls and 1280 boys of the average age of 20 months have undergone the auditory screenings in the Department of Phoniatrics and Audiology 3382 DPOAE, 1753 ABR and 1020 impedance audiometry tests were carried out.

Three groups were selected :

1.

Children with the pass result in acoustic otoemission measurement and who had no history of hearing loss risk factors.

2.

Children with the refer result in acoustic otoemission measurement.

3.

Children with hearing loss risk factors, who had the pass or the refer result.

According to the rule of cross-check children from the refer group have undergone the impedance audiometry and ABR test (recording auditory potential from the brain stem) determining the hearing threshold, what lead to diagnosis (norm; conductive, mixed or sensoryneural hypoacusis). 8.7% (218) of children who have undergone the screening were diagnosed with hearing loss less then 40 dB were fitted with hearing aids and started auditory training combined with surdologopedic rehabilitation. 2.6% (65)of children have been qualified to undergo the cochlear implant. 2.4% (59) of children were implanted with CI before 2 years of age.

A detailed analysis of screening was carried out in 2007 on the group of 510 children, with the following results:

hypoacusis was not confirmed in 68% children,

sensorineural hypoacusis in both ears in 16% children,

sensorineural hypoacusis in one ear in 7% children,

conductive hypoacusis in 10% children.

In 2007 there were 28 cochlear implantation operations performed in children in pre-school age (seven or less years of age). The average age of operated children was 38 months.

Efficient implementation of universal auditory screenings is possible only when 95% of the entire population of neonates is included. According to Program Board data 98.14% of all newborns have been examined in Poland. Application of the PPBSN program in Poland has two main goals. First of all, testing the hearing in the whole population of neonates in the first days of their life. Second, early detection of congenital hypoacusis. These goals were achieved. The screenings allowed for early use of hearing aid and rehabilitation of children with hypoacusis, what lead to lowering the average age of children qualified for deafness surgery treatment. It was necessary to apply a fast and simple diagnostics method to achieve these goals, maintaining proper rules of sensitivity and statistic specificity. Acoustic otoemission measurement was the best common method of auditory testing on neonatal wards. It was possible to obtain a result confirming good hearing in over 95 per cent of examined population.

Conclusion

Hearing aid, auditory training and rehabilitation of the communicative process beginning at the age of 6 months make the development of a child suffering from congenial hearing loss similar to other children of its age with normal hearing. Children with profound sensoryneural hypoacusis in both ears diagnosed in the PPBSN program, without sufficient gain from hearing aid, may be qualified to the cochlear implants program after only 6 months of rehabilitation, at the age of approximately 12 months.

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